Distributed computing systems as well as distributed computing services have become widely available in recent years. Such services and/or systems may, in some cases, be geographically and/or logically separate from one or more clients or users subscribing to the services. These services may include one or more computing devices configured to act as machine instances (e.g., virtual processors) and/or storage resources (e.g., virtual disk drives), for example. To access such services, clients may provide network addresses indicating computing devices where secure and/or private data is to be transmitted. The computing devices may be client or user computing devices. However, managing and/or verifying these network addresses may pose challenges to the service providers as well as the clients.